A conventional method of protecting electronic systems from an over-current condition (that is, a condition when more than a predetermined amount of electric current is drawn from the power supply) is by using a separate power supply for each subsystem, together with a circuit breaker, or a replaceable fuse, along with each power supply, so that, when an over-current condition occurs, the fuse will melt, or the circuit breaker will trip, thereby disconnecting the power supply from the subsystem.
When the number of subsystems becomes large, the use of separate power supplies, together with the corresponding number of fuse boxes required, will take up a significant amount of physical space. In addition, when the number of subsystems increases, the task associated with storing spare fuses and replacing melt fuses may become cumbersome.
Accordingly, there is a need for an electronic circuit which can perform the function of a fuse for protecting electronic systems from an over-current condition. However, it is also desirable to have a protection circuit which requires no fuse replacement, or no resetting of a circuit breaker, after the occurrence of an over-current condition.